1. Field of the Invention
The present invention relates to a power storage system, and more particularly to a power storage system which uses a secondary battery.
2. Description of the Conventional Art
In an electric charge of a secondary battery in a power storage system in which the secondary battery and a battery charger are combined, a constant current charge and a constant voltage charge are provided. The constant voltage charge detects an output voltage of the battery charger and controls the output voltage to a constant voltage so that the battery charger controls the output voltage to a predetermined constant voltage.
In the electric charge of the battery as mentioned above, in order to accurately charge the battery to a prescribed amount safely without deteriorating a service life, it is necessary to enhance a precision for detecting the output voltage of the battery charger, and calibrate the output voltage of the battery charger at the time of shipping products.